Why buy this?

• E&J are a leading electronics manufacturer who supply many well known brands.  This is the E&J branded model.
• The BM21 Bluetooth battery monitor allows you to monitor the status of your battery on the LCD display or on your iPhone or Android device.
• It is not just a simple voltmeter, it measures current and state of charge.
• Extensive research shows this type of shunt meter is more accurate than Hall sensor alternatives.
• Very low standby current compared to some alternative products.
• Lithium battery compatible.
• Also sold as Sterling AMPS – Battery Monitor BM1 but with shorter 1m display cable.

Key Features

This battery monitor is a high precision power management device. The shunt will accurately measure discharge and charge at any given time.

The device monitors your battery bank and DC circuits, giving you accurate information on :

• Remaining battery capacity (measured both as amp hours and as a percentage reading).
• Battery bank voltage.
• Current passing the shunt at any given time.
• The App will also provide history and data-logging for your system.

Alternatives

• An alternative is to use a Bluetooth shunt but this does not provide a convenient permanently on, easy to use display.
• An alternative type of meter is a “Hall Sensor” which allows faster installation by clamping around the battery cable.  These types of shunt have up to 5% inaccuracy – this can be a major issue when relying on state of charge, since you can accidentally over-charge and over-discharge your battery regularly –  damaging your expensive battery system.

Compatibility

• Compatible with Lithium, AGM, GEL, lead-acid and nickel-metal hydride battery types.
• Suitable for 12V, 24V, 36V, 48V batteries.
• Flush mount only.

What’s included

• 1 x E&J Bluetooth battery monitor.
• 1 x 500A shunt (for measuring current flow).
• 1 x 5m shielded wire (so can mount the display 5m away from the battery) – this kit is upgraded from the standard 1m cable.
• 1 x 1m battery positive wire.
• 1 x Display mounting bracket with butterfly nut.
• 1 x User manual.

Other parts needed for installation

• Battery cables.
• 54mm hole saw.
• 1A fuse and holder (recommended).

Specifications

• Shunt capacity: 500A.
• Working voltage: 8-80V.
• Low standby current: 0.8mA at 12V.
• Reverse polarity protection.
• Ah capacity: 0.1-999Ah.
• Temperature: 0-35°C.
• Voltage accuracy: ±1%.
• Current accuracy: ±1%.
• Capacity accuracy: ±1%.